// SPI引腳初始化

void W25X_SPI_Init(void)

{

RCC->APB1ENR |= RCC_APB1ENR_SPI2EN; // 打開(kāi)SPI2的時(shí)鐘

RCC->AHBENR |= RCC_AHBENR_GPIOBEN; // 打開(kāi)SPI2對(duì)應(yīng)引腳的時(shí)鐘

GPIOB->AFR[1] &= ~0xfff00000; // 開(kāi)引腳復(fù)用功能對(duì)應(yīng)的功能

// 配置GPIO

// cs口為通用輸出口，手動(dòng)控制cs

GPIOB->MODER &= ~GPIO_MODER_MODER12_1;

GPIOB->MODER |= GPIO_MODER_MODER12_0;

SPI_CS_H;

// 其它引腳為復(fù)用功能

GPIOB->MODER |= (GPIO_MODER_MODER13_1 | GPIO_MODER_MODER14_1 | GPIO_MODER_MODER15_1);

GPIOB->MODER &= ~(GPIO_MODER_MODER13_0 | GPIO_MODER_MODER14_0 | GPIO_MODER_MODER15_0);

GPIOB->PUPDR &= ~(GPIO_PUPDR_PUPDR14_1);

GPIOB->PUPDR |= (GPIO_PUPDR_PUPDR14_0);

GPIOB->OSPEEDR |= (GPIO_OSPEEDER_OSPEEDR12 | GPIO_OSPEEDER_OSPEEDR13 | GPIO_OSPEEDER_OSPEEDR14 | GPIO_OSPEEDER_OSPEEDR15);

// SPI2配置

SPI2->CR2 |= (SPI_CR2_DS_0 | SPI_CR2_DS_1 | SPI_CR2_DS_2 | SPI_CR2_FRXTH); // 8位數(shù)據(jù)模式

SPI2->CR1 |= (SPI_CR1_CPOL | SPI_CR1_CPHA | SPI_CR1_MSTR | SPI_CR1_SSM | SPI_CR1_SSI); // 主機(jī)模式。clk默認(rèn)高電平，第二邊沿驅(qū)動(dòng)（上升沿）

SPI2->CR1 |= SPI_CR1_SPE; // SPI使能

}

// SPI在發(fā)送數(shù)據(jù)的8個(gè)條邊沿的時(shí)間內(nèi)，也接受了8位數(shù)據(jù)

// SPI可以發(fā)送和接受在同一個(gè)8段跳邊沿之內(nèi)

unsigned char W25X_Write_And_Read_Dat(unsigned char write_dat_temp)

{

unsigned char read_dat_temp;

while(!(SPI2->SR & SPI_SR_TXE));

*(__IO uint8_t *)((uint32_t)SPI2+0x0c) = write_dat_temp; // 發(fā)送8位數(shù)據(jù)

while(!(SPI2->SR & SPI_SR_RXNE));

read_dat_temp = *(__IO uint8_t *)((uint32_t)SPI2+0x0c); // 接受8位數(shù)據(jù)

return read_dat_temp;

}